lnk{-}decl($l$; ${\it dt}$) $\,\equiv$$_{\mbox{\scriptsize def}}$$\;\;$$<$map(($\lambda$${\it tg}$.rcv($l$,${\it tg}$)); (${\it dt}$.1)), $\lambda$$k$.fpf{-}ap(${\it dt}$; id{-}deq; (outl($k$).2))$>$